The present invention relates generally cooling heat generating objects, such as electronic solid state and integrated circuit devices. More specifically, the present invention relates to apparatuses for dissipating heat generated by such devices.
In the electronics and computer industries, it has been well known to employ various types of electronic device packages and integrated circuit chips, such as the PENTIUM central processing unit chip (CPU) manufactured by Intel Corporation and RAM (random access memory) chips. These integrated circuit chips have a pin grid array (PGA) package and are typically installed into a socket which is soldered to a computer circuit board. These integrated circuit devices, particularly the CPU microprocessor chips, generate a great deal of heat during operation which must be removed to prevent adverse effects on operation of the system into which the device is installed. For example, a PENTIUM microprocessor, containing millions of transistors, is highly susceptible to overheating which could destroy the microprocessor device itself or other components proximal to the microprocessor.
In addition to the PENTIUM microprocessor discussed above, there are many other types of semiconductor device packages which are commonly used in computer equipment, for example. Recently, various types of surface mount packages, such as BGA (ball grid array) and LGA (land grid array) type semiconductor packages have become increasingly popular as the semiconductor package of choice for computers. For example, many microprocessors manufactured by the Motorola Corporation, for use in Apple Corporation computers, employ BGA-type packages. Unlike a PENTIUM microprocessor with a PGA package, which has pins to be installed into a receiving socket, BGA and LGA semiconductor packages include an array of electrical contacts on their bottom surfaces to engage directly with an array of receiving electrical contacts on a circuit board, socket or the like. These semiconductor device packages are either soldered directly to a circuit board or positioned within a socket.
In similar fashion to the PENTIUM-type semiconductor devices discussed above, the BGA, LGA and related device packages also suffer from excessive generation of heat. If such heat is not properly dissipated, the chip will eventually fail. This is particular true when the semiconductor device is mounted on a circuit board in a cramped environment, such as in a laptop computer. In this environments, a balance must typically be made between the space available and the heat dissipation required for the semiconductor package. Typically, the space available above the semiconductor device to be cooled is very limited. As a result, a cooling solution cannot be provided on the top of the semiconductor package.
In light of the limited space above the semiconductor package, a cooling solution must be provided from below the heat generating semiconductor device package.
However, conventional heat sink assemblies cannot affix to the semiconductor package from below because the package is typically mounted on a circuit board and little room is provided to enable the tension of the heat sink assembly to be easily adjusted. For example, in the prior art, a heat sink assembly can be simply fastened to the bottom of the circuit board and into communication with the bottom a the semiconductor package via a pass through bore in the circuit board. This direct fastening does not permit adjustment the tension of the physical communication of the heat sink and the bottom of the semiconductor package to be easily adjust. This creates a risk that too much pressure will be provided causing the electrical mounting of the semiconductor package to the circuit board to be severed. Or, if too little pressure is provided, flush thermal communication of the heat sink to the bottom of the heat generating semiconductor package will not be achieved resulting is poor heat dissipation.
In view of the foregoing, there is a demand for a heat sink assembly that can achieve high thermal conductivity and heat dissipation. Further, there is a demand for a heat sink assembly that is compact and can be reverse mounted to the bottom of a heat generating semiconductor device package with a fully adjustable contact tension. Moreover, there is a demand for such a heat sink assembly that can be easily installed and manufactured at low cost. In additional, there is a demand for a reverse mount heat sink assembly that can be easily removed when desired.